This application is the U.S. national phase of international application PCT/GB01/00760 filed Feb. 23, 2001 which designated the U.S.
This invention relates to an acceleration system for accelerating a load, and particularly, but not exclusively, to an aircraft launching system.
In GB 1 145 137 A, there is described an aircraft launching system comprising a cable, an end portion of which is adapted for releasably coupling with an aircraft and a remote end portion of which is secured. The cable is entrained in a pulley system, which includes a mechanism for accelerating the cable in a longitudinal direction so as to launch an aircraft coupled to the cable. The mechanism comprises a flywheel and a two-speed transmission coupled to the flywheel by a multiple disc friction clutch. The arrangement is such that the aircraft is accelerated slowly at first, for a distance approximately a quarter of the launch distance, and then accelerates rapidly to reach take-off speed.
In U.S. Pat. No. 1,734,353 A, there is described an aircraft launching system comprising a cable, an end portion of which is adapted for releasably coupling with an aircraft and a remote end portion of which is secured. The cable is entrained in a pulley system, which includes a mechanism for accelerating the cable in a longitudinal direction so as to launch an aircraft coupled to the cable. The mechanism comprises a flywheel and a gear coupling a motor to the flywheel, a drum, adapted for rotation on an axis, the surface of which has a curved profile the radial dimension of which increases progressively from the said axis in an arcuate direction of the said axis, and a clutch to couple the drum to the rotating flywheel. The arrangement is such as to impart a uniform acceleration to the aircraft and have it reach take-off speed.
An objective of the present invention is to provide an acceleration system, which provides energy uniformly over a short time span.
According to the present invention there is provided an acceleration system comprising a cable, an end portion of which is adapted for releasably coupling with a load, a rotary member adapted for rotation on an axis and drive means for disengageably engaging with the rotary member so as to rotate the rotary member on the axis characterised in that the rotary member is provided with a surface for receiving a portion of the cable remote from the said end portion and the surface has a curved profile the radial dimension of which increases progressively from the said axis in an arcuate direction of the said axis.